<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01 Transitional//EN"
        "http://www.w3.org/TR/html4/loose.dtd">
<html>
<head>
    <title>Title</title>
    <script src="http://libs.baidu.com/jquery/1.9.1/jquery.js"></script>
    <script type="text/javascript">
        $(function(){
            $(".box").mouseenter(111,function(){
                alert("xx");
            })
        })
    </script>
</head>
<body>
<div class="box" style="width: 200px;height: 200px;background-color: #00b7ee">
    <div class="xbox" style="width: 50px;height: 50px;background-color: pink"></div>
</div>
<button type="button">按钮</button>
</body>
</html>